Figure 8. La vs. Ce, Nd, Th, Ta, and Zr. Immobile incompatible elements show good correlations with each other. Because the altered samples (open and solid symbols) fall on the trends defined by the fresher samples, alteration does not appear to have significantly affected the immobile incompatible-element abundances. Rhyolite sample 7647-I (161-978A-47R-1, 0-6 cm) with 9.9 wt% CO2 has 325 ppm Zr and thus plots off the graph.

Figure 8. La vs. Ce, Nd, Th, Ta, and Zr. Immobile incompatible elements show good correlations with each other. Because the altered samples (open and solid symbols) fall on the trends defined by the fresher samples, alteration does not appear to have significantly affected the immobile incompatible-element abundances. Rhyolite sample 7647-I (161-978A-47R-1, 0-6 cm) with 9.9 wt% CO₂ has 325 ppm Zr and thus plots off the graph.